Improvement in blast-furnaces



JAMES H..M cKER'NAN.

Improvement in Blast Furnaces.

N0.12 3,035;. Phtentedlan.2 3,1872.

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WI'PI YESSES INVENTUR Harms.)

STATES JAMES H. MCKERNAN, OF INDIANAPOLIS, INDIANA.-

IMPROVEMENT IN BLAST=FURNACES.

Specification forming part of Letters latenlv No. 123,035, dated January 23, 1872.

Specification describing certain Improvements in Blast-Furnaces, by J. H. MCKER- NAN, of Indianapolis, county of Marion and State of Indiana.

My improvement consists in the arrangement of certain parts of a blast-furnace in such a manner that dust that accumulates in the furnace from soft coal, which cuts off the free passage of the blast through the stock, can be removed; also, to remelt any iron that may become chilled on the hearth.

Figure 1 represents a vertical transverse section of a blast-furnace embodying my invention. Fig. 2 is an elevation of the same. Fig. 3 is a horizontal section through the line 2 2, Fig. 1. Fig. 4 is an enlarged section of the pipe E, connecting-pipe J, and outside pipe H. Fig. 5 is anenlarged section of the pipe H, showing the gas-vent y and drop-pipe.

Description of the Blast-Furnace.

A blast-furnace consists of two truncated cones, B C, joined at their bases. The bottom of the furnace D is called the hearth, and the lower part of the lower cone 0 is called the boshes, and is constructed of fire-brick, or of a very refractory material called fire-stone.

This part of the furnace is subjected to a very intense heat, and it is necessary to construct it of such material as may be sufficiently durable. The upper cone B or body of the furnace is formed of an internal lining of firebrick, which is again envelopedin a casing made up of broken scorize or refractory sand, whereby the internal lining or shirt of the furnace is separated from the external coating of fire-brick, which is supported by a mass of masonry, composed of stone and common stock brick, or an iron casing. The opening P at the top of the furnace is called the throat or tunnel-head, in which there are openings called filling-doors, used to supply the furnace with fuel, ore, and flux. Air is supplied to the furnace by tuyeres, which enter the furnace at Q, through which the blast is forced.

The height of the stack is about sixty feet, with a hearth six feet high. The bosh is fourteen feet in diameter at the intersection of the upper cone or body of the furnace, and is eleven feet from the top of the hearth to the top of the bosh. The height of the tuyeres is forty-seven inches from the bottom of the hearth, and there are twenty-five inches from the tuyeres to the top of the hearth or bottom of the bosh. About four feet above the top of the hearth is an opening or arch, T, in the bosh, and extends through the masonry to the outside. This opening is shown over the tappinghole in the shafts, but may be placed at any convenient place around the stack, (as at the side or back.) This opening or arch is used to inject fuel in case where the stock hangs in the furnace, whichis caused by the stock bridging over near the bottom of the bosh, and prevents the blast from passing up through the stock, and causes the furnace to become cold for want of the necessary fuel in the bottom of the furnace. To relieve this difficulty I use the arch T for the purpose of injecting the necessary fuel 5 then put in a large quantity of scrap and a small quantity of pig-lead to facilitate the purpose of cutting out the chill below. This gives vitality to the furnace. In the upper cone B of the body of the furnace, and about twenty feet below the top, is a se ries of twelve holes and twelve spaces of equal size, the holes radiating from the inside of the furnace to the outside, and are then connected to the outside pipe H by the pipes J J, which are curved in the proper way to enable the blast to carry the dust and gas without any obstruction to the outlet-pipe K. In lining the furnace about four feet below the holes E E, the spaces F F are carried up plumb to the bottom of the holes, and leaves the spaces G G tapered from the holes E E to their point, four feet below these spaces G G, having the same taper as the inside of the furnace. This arrangement leaves a recess, F, between the tapered space G G and under the openings E E. This allows the dust and gas to pass out of the furnace and, through the connectingpipes J J, into the main pipe H, which encircles the furnace. Here the dust and gas are parted in the center at 7, Fig. 3, and onehalf goes to the right and the other half to the left, and leaves the pipe H at the place where the pipe K is placed. The dust that does not get around to the pipe K is received in the droppipes 3 3, which are placed at convenient distances apart, and have drop -doors at their bottom end, and from these can be let out at pleasure by any one passing around the platform M for that purpose.

The effect of the above arrangement of recesses and openings in the upper cone B of the furnace is this: The blast has a powerful centrifugal force, which sends everything in the shape of dust and dirt from the center, and will keep stock in a good clear condition, while the supply of oxygen at the bottom will keep the fire in good condition. When it becomes necessary to stop up the furnace for want of stock or any other cause, the plugs U U, shown in Fig. 4, which are made of iron and fire-clay, are passed through the gas-Vents in the pipes J J, and inserted into the pipes or openings E E; and a bar of iron, V, having a screw, X, through its center, is inserted and the ends placed against the flange of the pipe J J, or against the inside of the iron casing that surrounds the furnace, and the screw X is tight ened up against the rear end of the plug U, thus securing it in its proper position.

Claim.

Witnesses:

S. O. FRINK, WM. H. A. DELL. 

